A biphasic response of urinary prostaglandin E2 excretion to water deprivation in conscious diabetes insipidus Brattleboro rats.

Abstract The effects of water deprivation on the urinary excretion rate of prostaglandin E 2 (PGE 2 ) were examined in conscious Brattleboro rats. In order to study the time course of the changes in the PGE 2 excretory rate, urine was collected in 6 periods, Control: 0–1 hour (h.). I: 3–4.5 h., II: 8–10 h., III: 12–15 h., IV: 24–28 h. and V: 32–36 h. after removal of water and food. It was found that the PGE 2 excretion rate changed in a biphasic pattern. During the first 2 experimental periods it increased. Thereafter it decreased towards the control value. There was an increase in PGE 2 excretion with urinary flows down to 3 μl/(min ∗ 100 g b. wt.). At further reductions in urinary flow rate, PG excretion decreased towards basal levels.